A control device configured to secure the safety of a vehicle at a vehicle collision by controlling an electric motor to step out is proposed in, for example, Patent Literature 1. More specifically, upon detection of a vehicle collision, the control device sets a command value for an inverter to an operating frequency at which the electric motor cannot be driven. Consequently, the control device discharges high-voltage charges accumulated in a capacitor connected to an input side of the inverter by a switching loss of the inverter while restricting generation of a torque in the electric motor.
According to the technique in the related art as above, however, when a capacitance of the capacitor is small for energy of the electric motor, energy stored in the electric motor at an onset of a collision is regenerated and charged to the capacitor. A voltage exceeding a breakdown voltage is thus applied to the capacitor. Such a voltage application raises a problem that the capacitor breaks before a discharge of the capacitor is completed. Once the capacitor breaks, a discharge is no longer feasible.